Etching simulation of negative sloped planes at convex mask corners in Si

Using a cellular automata model, a new approach to simulate negative sloped planes, which often appear underneath convex mask corners in wet chemical etching of semiconductors, is presented. The main idea of the simulation method is the simplification of the three-dimensional (3D) problem through virtual dismantling of the substrate into layers parallel to the mask. Every layer is then two-dimensionally treated. The new method is applied to the etching system Si in KOH resulting in good agreement between simulation and experiment.